Topping out at Heathrow's new terminal

In a "topping out" ceremony, Mr Darling and Mike Clasper, the chief executive of airport operator BAA, helped lay a slab of concrete on the departures floor of the 1,300ft-long building.

Due to open in March 2008, T5 has been built on an old sludge works at the western end of the airport in west London.

T5 will enable British Airways to base its operations at Heathrow in a single terminal which will be able to cater for more than 30 million passengers a year.

Mr Darling said today: "Terminal 5 will provide Heathrow with a new world-class terminal - a spectacular first impression for passengers arriving at the airport.

"The Government is determined to do all that it can to ensure Heathrow's important position in the world."

Mr Clasper said the new terminal would be opening in fewer than 950 days and that passengers would "experience one of the finest airport facilities anywhere in the world and the newest gateway to London and the world".

T5 managing director Tony Douglas said: "Three years ago we set out to build Terminal 5 and on budget. Now, with the building almost two-thirds complete, we are hitting all our targets."

Opposition

The new terminal has been bitterly opposed by local residents and environmental groups and was the subject of a record-breaking four-year public inquiry from 1995 to 1999.

Work started on the project in September 2002 and the 2008 opening will be the first phase of the completion of the entire project.

In March 2008 the main terminal and first satellite building will open, with a second satellite building being completed in phase two by 2011.

The T5 site is equivalent in size to London's Hyde Park and the main terminal building is 590ft wide and 130ft high. The main terminal has 105 lifts and 65 escalators and the entire T5 will require 80,000 tonnes of structural steel.

T5 will be linked to both the Heathrow Express mainline railway and London Underground's Piccadilly line.

Two rivers were diverted around the perimeter of the T5 site and BAA will be planting 30,000 native woodland plants, 1,500 semi-mature trees and 2,500 semi-mature shrubs over the next two years.

Around 6,500 people are working on T5. Construction workers, suppliers, aviation staff and local community representatives were among those present at today's topping-out ceremony.